In recent years, in sound reproduction, a so-called surround system has been employed and various methods of allowing a user to change a direction or an installation position of a speaker by hands have been employed in order to improve a feeling of presence in a two-channel stereo system.
Of these methods, a technology of allowing a user to directly change a direction of a speaker by hands has an advantage that can improve the user's visibility with respect to sound by adapting to the user's taste. As an example of a literature disclosing the relevant technology, Patent Literature 1 discloses a technology of a speaker device including a housing assembly that is installed such that a grill is protruded from a wall by a case incorporating a speaker and the grill provided at a front opening side thereof, and an attaching mechanism that attaches and fixes the speaker to a desired angle position by rotating the speaker with respect to the housing assembly, wherein the attaching mechanism can be operated at the grill side protruded from the wall. According to the configuration, the user can directly rotate a speaker unit by hands and fix the speaker unit at a desired angle. However, in the technology described in the Patent Literature 1, the operability to directly rotate the speaker unit by the user's hands has been relatively bad.
Also, for example, Patent Literature 2 discloses a technology configured to mount a speaker unit to a rotation chamber, support a rotational axis provided in the rotation chamber through a bearing provided in a fixed chamber, and drive a circular arc-shaped gear, which is provided in an outer periphery of the rotation chamber, by a motor through another circular gear.
However, in the technology described in Patent Literature 1 or Patent Literature 2, it is possible to change the angle only in a straight line direction such that the direction of the speaker becomes a vertical direction or a horizontal direction, and the direction of the speaker could not be appropriately and arbitrarily changed.
Further, for example, Patent Literature 3 discloses a technology that includes a rotation reference face forming means forming a rotation reference face, a rotation face forming means forming a rotation face capable of rotating along the rotation reference face, and a speaker mounted on the rotation face forming means such that the speaker is inclined at a predetermined angle with respect to the rotation reference face, wherein the orientation of the reference axis of the speaker can be changed by the rotation of the rotation face forming means.
However, the orientation of the reference axis of the speaker can be merely changed by the rotation of the rotation face forming means, and the direction of the speaker could not still be appropriately and arbitrarily changed.